They’re extremely mild implications of the exact shape you’d expect actual guards to get while on the job, no?

Is your thinking that a prison guard (or analogous) would be told to be kind and forgiving, or not given any direction at all on the “right” way to behave?

Nitpick: those might be euphemisms but they’re not dog whistles. Everyone, not just some kind of people would understand the unstated meaning of those words.

Dog whistles are similar to shibboleths.